Unix cmp utility — report differing byte numbers and values in octal Which cmp option produces a detailed list of each differing byte position along with the differing byte values in octal for two files being compared?

Introduction / Context:
The cmp command is a binary comparator used to identify differences between two files. While its default output is minimal, certain options enable detailed byte-by-byte diagnostics, which are invaluable for debugging binary data or investigating subtle file corruption.

Given Data / Assumptions:

• We are comparing two files with cmp.
• We want a detailed list of differences: byte offsets and byte values.
• Output should show octal representations of differing bytes.

Concept / Approach:

cmp -l file1 file2 outputs each mismatch as a line containing the 1-based byte position, the byte value from the first file in octal, and the byte value from the second file in octal. This contrasts with the default behavior, which only reports the first difference and stops. Other options change exit behavior but do not produce this detailed listing.

Step-by-Step Solution:

Verification / Alternative check:

Create two small files with known byte differences and compare them. Verify that the listed byte numbers and octal values match expectations. You can cross-check with od -An -tx1 -v or xxd for hex dumps.

Why Other Options Are Wrong:

• -d: not the detailed octal difference listing in standard cmp.
• -r: nonstandard for cmp; often relates to recursion in other tools.
• -b: not the correct cmp verbose setting for octal differences.
• None of the above: incorrect because -l is correct.

Common Pitfalls:

Expecting 0-based positions (cmp uses 1-based); misreading octal values as decimal or hex; assuming cmp behaves like diff, which is line-oriented rather than byte-oriented.

Final Answer:

-l